Dipeptidyl peptidase IV in human T lymphocytes. An approach to the role of a membrane peptidase in the immune system.

Dipeptidyl peptidase IV (DP IV), an ectoenzyme in the cell membrane of human T lymphocytes, is an important constituent in the process of lymphocyte activation and proliferation. In the presence of specific inhibitors and antibodies against DP IV several in vitro functions of activated lymphocytes were found to be impaired. These include mitogen induced DNA synthesis, immunoglobulin secretion and production of interferon-gamma. The functional importance of DP IV during activation of lymphocytes is underlined by an increase in cellular DP IV activity upon mitogenic stimulation.